Higher Risk of Autism Found in Children Born at Short and Long Interpregnancy Intervals

Reports new
study in Journal of the American
Academy of Child and Adolescent Psychiatry

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Washington D.C., September 24, 2014

A study
published in the MONTH 2014 issue of the Journal of the American Academy of
Child and Adolescent Psychiatry found that children who were conceived either
less than 1 year or more than 5 years after the birth of their prior sibling were
more likely to be diagnosed with autism than children conceived following an
interval of 2-5 years.

Using
data from the Finnish
Prenatal Study of Autism (FIPS-A), a group of researchers led by Keely
Cheslack-Postava, PhD, of Columbia University, analyzed records from 7371 children
born between 1987 and 2005 in Finland. Roughly a third of the children had been
diagnosed with autism, while the rest were drawn from other births occurring at
similar times and locations. The study used information from several national
registries to compare the spacing of pregnancies between the children who had
been diagnosed with autism and those who had not.

The study
found that the risk of an autism diagnosis among children conceived less than 12
months following a sibling's birth was one and a half times as high as those
conceived following an interval of 24-59 months. Children conceived following
an interval of 60-120 months were almost 30% more likely to be diagnosed with
autism. For intervals of more than 120 months, the risk of autism was over 40%
higher.

The
analysis accounted for certain factors that might explain the association, such
as parents' age, prior number of children, and parental history of psychiatric
disorders.

The FIPS-A
is a case-control study based in a national birth cohort consisting of all
children born in Finland from 1987-2005. It makes use of linked national registries
and archived serum samples.

Dr. Cheslack-Postava said of the study, "It was intriguing
to see that the risk of ASD diagnosis was higher in both closely and distantly
spaced pregnancies. It is important to realize that we can't say from this
study that spacing of pregnancies per se is a cause of ASD—this is most likely
a proxy of other factors that are more directly related to the chance of the
child's developing ASD. In other words,
the importance of this finding lies in the clues that it can provide in terms
of understanding how the prenatal environment is related to outcomes after
birth."

The senior author of the study, Dr. Alan Brown of Columbia
University, said, "This study provides further evidence that environmental
factors occurring during or near the prenatal period play a role in autism, a
serious and disabling condition that afflicts millions of individuals and that
is increasing in prevalence. This work
also exemplifies the importance of large samples of pregnancies with data
acquired during pregnancy and their linkage to comprehensive, national databases
of reproductive factors and psychiatric diagnoses."

A
related editorial, "Sizing Up the Search for Autism Spectrum Disorder (ASD)
Risk Markers During Prenatal and Early Postnatal Life," by Dr. Armin Raznahan,
is published in the same issue (http://dx.doi.org/10.1016/j.jaac.2014.07.010).

This
study was funded by the National Institutes of Health (NIEHS R01ES019004
[A.S.B.], NIMH K02 MH065422 [A.S.B.], and NIMH T32-13043 [K.C.P.]), the Turku
University Foundation (E.J.), and the Finnish Epilepsy Society (E.J.).

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Notes
for editorsFull text of the article is available to credentialed
journalists upon request; contact Mary Billingsley at +1 202 587 9672 or mbillingsley@jaacap.org.
Journalists wishing to interview the authors may contact Keely Cheslack-Postava
at kc2497@columbia.edu
or Alan Brown at asb11@columbia.edu or
646-774-6417.

All articles published in JAACAP are embargoed until the day they are published as in press
corrected proofs online at http://jaacap.org/inpress.
Articles cannot be publicized as in press accepted manuscripts. Contents of the
publication should not be released to or by the media or government agencies prior
to the embargo date.

About JAACAPJournal of the American Academy of Child and Adolescent
Psychiatry (JAACAP) is the official publication of the American Academy of
Child and Adolescent Psychiatry. JAACAP is the leading journal focusing
exclusively on today's psychiatric research and treatment of the child and
adolescent. Published twelve times per year, each issue is committed to its
mission of advancing the science of pediatric mental health and promoting the
care of youth and their families.

The journal's purpose is to advance research, clinical practice,
and theory in child and adolescent psychiatry. It is interested in manuscripts
from diverse viewpoints, including genetic, epidemiological, neurobiological,
cognitive, behavioral, psychodynamic, social, cultural, and economic. Studies
of diagnostic reliability and validity, psychotherapeutic and
psychopharmacological treatment efficacy, and mental health services
effectiveness are encouraged. The journal also seeks to promote the well-being
of children and families by publishing scholarly papers on such subjects as
health policy, legislation, advocacy, culture and society, and service
provision as they pertain to the mental health of children and families.

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